Ah, yes. Bra talk. My go-to. xD
Basically, all you need to know is: your cup size is nothing without your band size. A “C cup” is a meaningless measurement if you don’t have a number to go along with it.
Chart courtesy of Fuller Figure, Fuller Bust
How you get your band size is by taking a measurement of your chest, directly under your breast tissue (this is where the bra band will sit):
If you get an uneven number, like say 37, you can round it up to an even one, like 38. Or, you can keep it at 37 and deal with the rounding up or down, later. We’ll get to that.
Now take a measurement of your chest across the nipples. This is the measurement you will use to determine your cup size.
Use this site here to enter your data. It will tell you your bra size, and has the added benefit of telling you the various options available depending on the fit you want. If you’re extremely pressure sensitive (like I am, lately), it would be better to opt for a looser band.
I entered “37” for underbust (rib cage measurement) and “45” for overbust (nipple measurement) as my examples. For this chart you’ll notice “North American equivalent”- that is for buying bras in USA sizing. Each area and country has a different bra sizing, it can get confusing; The UK’s cup sizes are one letter smaller than the USA’s. Australia has one this system where they go with 10s and what not- I don’t know, they rarely have my size so I don’t fuck with it. Euro sizes aren’t too dissimilar from the UK, iirc.
The example measurements give me a UK size of 36GG, with a US size of 36I. You’ll sometimes notice the double-cup-size letters (like “GG”). I really don’t have an explanation for them: some companies use them as a substitute for the next letter over (like H) because of size stigma (most often seen in “DD” being used instead of “E”), some use them as half sizes (like a G.5, so to speak). The difference between your overbust and your underbust gives you your cup size. (This hails back to me saying the cup size is nothing without the band size- a 34C is a different volume than a 32C- as shown in that color-coded chart earlier).
One other thing I explained in chat:
Your bra underwire should properly “cradle” all your breast tissue. If there’s overlap, it doesn’t fit.
Example, courtesy of FFFB (bra on the left fits, bra on the right does not fit…not even close):
Yet another thing is the “gore” of the bra- essentially the center of the bra.
Number 5 in this picture. The gore is meant to sit flat against the center of your chest (flat against the sternum). One immediate way to tell your bra doesn’t fit is if there is a space between the gore and your chest. I showed you an example of wearing a bra that doesn’t fit and being able to fit let a pencil drop between the gore and my chest. The reason that happened was because my breast tissue was literally pushing the bra cups away- the bra was too small, the cups were too small, and there was not even space for the breast tissue to sit comfortably. That’s why that happens. If you have the right band size, but the wrong cup size, your breast tissue will literally push the cups away in a bid to occupy space.
On rare occasions you will find the gore of a bra will not sit down properly, despite it being the proper size: this is due to the fundamental structure of the bra not being compatible with your anatomy. If it’s still comfortable, the right size, and you feel supported, then “eh” is all I say to that. I have a sports bra like that. It fits, but it’s structure is in opposition to mine, so the gore will never sit fully. As long as you feel supported, it’s fine.
Hope that helps, let me know if you need any clarification.
And you know your band is too big for you if it slides UP.
Noooooooo. This also causes your cups to fall down. This is a completely unsupportive bra, all around. Bye, bra, bye.
And buying a bra in a similar volume is not a standard, it’s still best to get the bra that originally fits you.
Example, courtesy of “Thin and Curvy”
Again, the exception being comfort: if the band is too tight for you, by all means go for a looser band (and you’ll need to adjust your cup size for volume accordingly- luckily that bra measuring website I linked does that for you!). On bad pain days, my tighter-banded (same size, different brand and type) will just irritate my pain and sensory issues to no end. On those days I opt for my (still fitting band size) looser bra, or even no bra.